All I can go by is what's on the site then. They do not indicate 40mhz is available. It if is....I'm not sure.
Crystals come in single and dual conversion. You can get them on the same channel but they are not interchangeable. Maybe you have the wrong one?
Crystals are also fragile. Drop them and they can break. You can't see the damage.

fly
If you're going to learn to fly them, you have to learn to fix them.

All I can go by is what's on the site then. They do not indicate 40mhz is available. It if is....I'm not sure.
Crystals come in single and dual conversion. You can get them on the same channel but they are not interchangeable. Maybe you have the wrong one?
Crystals are also fragile. Drop them and they can break. You can't see the damage.

brand new cristles m8. bort form hobby shop as a pear lol no info on it at all lol

In the USA, 72 MHz is the US standard for airplanes. 75 MHz is surface only.

2.4 GHz can be used for air or surface.

27 MHz is air or surface but mostly found in toys for the last zillion years.

BTW, this is very old equipment.

One does not "bind" a 27 MHz, 40 mhz, 72 MHz or 75 MHz radio. No such thing as binding.
you say they are both on 40 MHz. do you mean they are both on channel 40? Neither this receiver or this radio is available on 40 MHz that I can tell.

Hitec do/did make 40Mhz gear because that's the surface frequency in the UK and many other countries.

The DCX is a DUAL CONVERSION FM receiver so it needs Hitec DC crystal in it. Must be Dual Conversion and must be Hitec make. The transmitter crystal must also be Hitec. Both transmitter and receiver crystals should be on the same channel.

If that's all o.k., you have power to everything and it still doesn't work then you've probably got a bad one .